Air accumulation canisters that are currently available in the market are often constructed by a hollow cylindrical canister having opposite ends to which end caps are mounted and sealed by welding. The conventional air accumulation is realized by continuously pumping air into the air accumulation canister through an air compressor. When the amount of air pumped into the canister is increased, the air density inside the canister is also increased. Due to a fixed volume that is provided by the conventional canister, the increasing of the air density causes an increase of the internal pressure of the canister. Due to limited strength of the structure of the canister, the internal pressure cannot exceed an upper limit and thus the amount of air that can be stored inside the canister is limited. When the air is released from the canister, with the amount of the air inside the canister decreased, the internal pressure is also reduced. Thus, the air supplied from the canister is at released at a varying pressure and the pressure is of the low extreme when the canister is going to run out of air.
In tidal power generation facility, an air accumulation canister is used to store pressurized air and to stably discharge airflow of substantially constant pressure for driving a turbine that in turn drives a generator to generate power. The conventional air accumulation canister, however, is not satisfactory in both mass storage of air and stable supply of air at constant pressure. Thus, the present invention is aimed to provide a device for effective mass storage of air and stable supply of constant pressure air flow to suit at least the need mentioned above.